Mealybugs prefer climates with warm weather and mild winters, but also thrive on indoor plants. This insect is part of the Pseudococcidae family, found in warm and moist environments. Mealybugs are found throughout the United States and infest many different species of plants. They feed on the juices of subtropical trees and plants and carry several different plant diseases. They often attract ants and create sooty black mold due to the production of honeydew. In several of the photos on this page, you will notice ants are present.
Mealybugs are covered in wax and feed on numerous types of plants including outdoor gardens & crops and indoor houseplants. The piercing and sucking insects generally move in colonies. Mealybugs have a close relation to soft scales, but the difference is they do not have scale covers.
What do Mealybugs Look Like?
The insects drain the moisture from the inside of the plant and can kill the plant, if not controlled, by sucking out all the juices. Look for this pest where there is new growth, or where the stem connects to the leaf. Most of these insects are white, but they can also have a light pink coloration.
Female mealybugs are wingless, slow-moving and white. They feed in large colonies. The crawlers or nymph eggs are yellowish orange. The coloration of the nymphs is red to a yellowish white, eventually excreting wax of a whitish color. The bodies of the mealybug nymphs are also waxy, flat and soft, with a unique body segmentation and an oval shape.
One of the best ways to know mealybugs are present is with white eggs sacs resembling cotton. The sacs contain a maximum of 100 mealybug eggs. The size of a mealybug is dependent on the species, with a length between one-twentieth and one-fifth of an inch. The bodies are oval, with waxy filament fringe and parallel and distinctive segments.
The pests look a lot like spots of cotton, including the waxy cover encasing the eggs. The appearance of the adult males is completely different. Although rarely seen, the males look like small, winged flies. If they are not controlled, there can be extensive damage to the plants.
What Causes Mealybugs?
One of the first questions most people have is what causes mealybugs? Due to the small size, they go undetected in numerous different sources including fresh produce purchased at a farmer’s market or grocery store, other plants and potting soil. This means, introduction by an infested plant is usually the cause. Always inspect new plants and quarantine them before introducing them to your growing space.
Many of these insects are found indoors, but some live outside. One of the first species identified is the pink hibiscus mealybug. It is also the most toxic.
This species originated in India, first seen in 1920 in Egypt. In 1993, the pest invaded the Caribbean, quickly spreading to the islands, and finally reaching Florida. Economic losses have been suffered by numerous states due to infestations in both nurseries and crops. Mealybugs have also invaded Alabama, California, Louisiana, New Mexico, South Carolina, Arizona, Georgia, Mississippi, North Carolina and Texas.
Mealybugs are most attracted to the high nitrogen levels found in numerous plants. Moist soil and over-fertilized plants increase vulnerability for an infestation. Learning how to get rid of mealybugs often means keeping these factors under control.
Mealybugs Life Cycle
The life cycle of mealybugs ranges from 6 weeks to 2 months and is dependent on the species as well as environmental conditions. Adult females lay between 300 to 600 eggs. After laying the eggs, the female dies. Between 7 and 10 days are required for eggs to hatch into nymphs or crawlers. Nymphs molt through several phases before becoming adults. Nymphs crawl around looking for new areas to feed, then anchor in these locations.
Rarely seen adult male mealybugs are tiny two-winged insects with two long tail filaments. The life of the males ends within one to two days after fertilizing an adult female. The adult males are unable to feed due to the lack of mouthparts and are often confused for fungus gnats. Many mealybug species can reproduce asexually without mating.
What Does Mealybug Damage Look Like?
The most frequently seen mealybug damage includes:
- White fuzz on the plants, soil or roots
- Drooping and yellowed leaves
- Sooty black mold
- Distorted growth
- Wilted or curled leaves
- Discoloration
- Prematurely dropping leaves
- Improperly formed fruit
- Dying small branches and twigs
The most common damage includes black sooty mold, distorted growth, and drooping and yellowed leaves. The plants are weakened when the mealybugs suck out the juices from the leaves and stems. Once damaged, the plants become discolored, curl and wilt. The fruit is often unable to form correctly. Small branches and twigs begin to die. The honeydew substance excreted by mealybugs develops into a sooty black mold.
An infestation is often accompanied by ants because they feed on the honeydew. Mealybugs decrease plant vigor by sucking sap from the plants. Large infestations of both the mealybugs and egg sacs result in an unattractive appearance, premature leaf dropping and slow plant growth. A lower number of mealybugs is tolerable without a lot of damage provided the plant is healthy.
The ground version of this species is not common in gardens, but often seen on indoor plants. This pest causes the plants to die by feeding on the roots. Unfortunately, the damage is not usually noticeable until the roots of the plant have been exposed. Mealybugs are especially attracted to perennial plants such as fruit trees.
Mealybugs can sometimes be seen on cannabis, as well as pome or stone fruits. The vine species will infest grapes, attacking both the roots and above the ground. Certain herbaceous perennials and woody ornamental plants become infested including coral bells, flax grasses, gardenia, jasmine, Miscanthus grasses, cactus, figs, fuchsia, hibiscus, mimosa and oleander.
The cypress bark species is a serious threat for urban areas, attacking cypress, juniper and cedar. The most vulnerable plants are those grown in greenhouses or indoors due to the mild temperatures throughout the year. These plants are not protected by the pest’s natural enemies responsible for controlling the population outside.
Commonly, the most infested indoor plants include coleus, ferns, Hoya, orchids, philodendron, poinsettia, aglaonema, cactus, dracaena, Ficus, date, palms, and herbs such as sage and rosemary. The ground species most frequently attacks gardenias and African violets. Some are responsible for the transmission of viruses, but this is generally not a threat for landscapes and gardens.
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How to Get Rid of or Kill Mealybugs Naturally
These pests can be killed in numerous ways including:
- Trifecta Crop Control
- Pruning leaves
- Parasitic wasps
- Removing mealybugs manually
- Discarding the plant
The best option is using a combination of different methods to determine which one is right for each situation. Some methods are more effective than others depending on the specific species and the environment.
One proven natural and organic method is using the power of essential oils. Peppermint and thyme are some of the most effective, which makes Trifecta Crop Control a great choice. Our customers have reported success when applying undiluted Crop Control Super Concentrate with a small paint brush.
Another option is using pruning shears to cut off any areas of the plant that have become infested. Prune off any stems or leaves with attached egg sacs. Once the plant has been pruned, dip the pruned sections into rubbing alcohol and allow them to soak for several minutes to make certain the mealybugs are dead before throwing them away. This process needs to be repeated every week until the population has decreased or is eliminated.
You can also successfully kill mealybugs by understanding different species of parasitic wasps. These predators can be attracted by planting bee balm, sweet alyssum and yarrow. The predators are attracted to the rich content of nectar. Other predators include pirate bugs and lacewings. Mealybugs can be manually removed with a paper towel or cloth. Make certain you squish the mealybugs when removing them. Wash out the cloth immediately.
When the insects are removed with paper towels, everything needs to be put into a plastic bag and discarded immediately. Be sure to remove any egg sacs when removing mealybugs. The sacs will be attached, resembling small balls of cotton. If the infestation is severe, the plant may need to be thrown away. Severe infestations are extremely difficult to control, and almost impossible to eliminate.
How to Prevent Mealybugs Naturally
- Apply Trifecta Crop Control as a preventative
- Visually inspect the plants
- Do not over-fertilize
- Regularly spray the (non-cannabis) plants with water to remove honeydew and sooty mold
- Make certain new plants do not have any pests before purchasing
We can’t stress the importance of being proactive versus reactive. Apply Trifecta Crop Control as a preventative at 1oz per gallon, once weekly to keep your plants pest, mold and mildew free!
All new plants should be carefully inspected for an infestation prior to purchasing. Over-fertilized plants are more attractive to the mealybugs due to soil rich in nitrogen. Plants should only be fed when necessary. Hosing the (sturdy, non-cannabis) plants down with a strong water stream on a regular basis will discourage the insects.
Mealybug Management in Greenhouses Using Biocontrols
Cryptolaemus Montrouzieri
Cryptolaemus is a native Australian predatory ladybird beetle. Cryptolaemus is extremely effective for all mealybugs producing egg masses like cotton. Both young larvae and adults consume mealybugs at every stage. The adult beetles are four centimeters in length with an orangish-brown coloration. Females lay ten eggs each day in groupings of mealybug eggs or colonies and live around two months.
The larvae hatching from the eggs grow to a length of 13 millimeters. You can recognize them by the lengthy waxlike and white filaments. The appearance of prey and larvae are easily confused due to the white secretion. The young larvae consume mealybugs in smaller stages and the bigger larvae consume all sizes. Sunny weather with a temperature of 68 degrees Fahrenheit and 70 to 80 percent humidity increase the activity of Cryptolaemus.
Two to five adults should be released for every plant infested. You can achieve control by repeating whenever necessary. Tips for Cryptolaemus use include:
- Cryptolaemus should be released at night on the day received
- Windows and vents must be shut the day of introduction
- Before introduction, you need to mist the area using water
- Avoid white clothing during introduction or you will attract the predators
- Adult beetles must never be stored in the containers for over 18 hours
- Pests will be protected by ants, so they must be controlled
- The predators are unable to fly during temperatures under 56 degrees Fahrenheit
- The beetles must be tapped gently from the container to infested foliage
- During the introduction, the humidity level should be between 70 and 80 percent
- White index cards should be placed as close to the hot spots as possible to help the predators find prey
Leptomastix Dactylopii
Leptomastix dactylopii is just three millimeters in length. You should only use this wasp to control citrus mealybugs because it is inefficient for any other species. For a heavier infestation, use both this parasite and Cryptolaemus. The leaves are searched by adult females for larger mealybug stages. A suitable host is located, then eggs are laid inside of the prey.
The emergence of the wasp is from the parasitized body. Between 50 and 100 mealybugs can be parasitized by a single wasp. When the temperature is 75 degrees Fahrenheit, the life cycle requires a period of roughly three weeks. Each infested square yard requires one to two adults with five required for each infested plant. The predator needs to be introduced one to two times per year. Tips for leptomastix use are:
- Do not use residual pesticides for four to six weeks before performing biocontrol
- Release predators as soon as citrus mealybugs are discovered
- Additional introductions may be necessary, so scout every seven days
- You need to be certain there are citrus mealybugs present before introduction
- Since this wasp walks, introduce to mealybug hotspots
- Introduce upon receipt
Cultural Control
- Perform a careful inspection for all new plants
- All plants with a mealybug infestation need to be isolated
- Discard plants with a heavy infestation
- Do not over-fertilize using nitrogen
- Mealybugs can be flushed away with water on sturdy, non-cannabis plants
- Pots must be cleaned thoroughly
- Inspect the edges of used trays and pots for crawlers and egg masses
